1. Field of the Invention
The present invention relates to fluid separation systems using such technology as reverse osmosis, ultrafiltration, absorption and ion exchange.
2. Discussion of Related Art
The use of ultrafiltration and reverse osmosis devices for various applications is becoming increasingly more prevalent. One example of a very important use for reverse osmosis elements is the production of potable water from seawater, brackish water, and non-potable fresh waters.
Currently available reverse osmosis water purification units contain a plurality of reverse osmosis elements which are installed in modules with up to five elements contained in a series arrangement within a single pressure vessel. This requires a multiplicity of high pressure, interconnecting fittings, valves and piping. In addition, because of the numerous plumbing connections, potential points of leakage are increased, especially in equipment which must be frequently disassembled. Also, it is very difficult and possibly unlikely that an operator in the field could determine which element in a series arrangement is defective when the product water is determined to be unacceptable. As a result, two or more expensive reverse osmosis elements may be replaced when only one element or possibly even the seal on one element is the cause of the unacceptable product water.
Other configurations have been suggested. For example, U.S. Pat. No. 4,016,078 to Clark discloses a header block for tubular membrane permeator modules The header block comprises two opposed, generally planar surfaces joined by a feed bore. The axis of the bore is perpendicular to the faces. A third generally planar surface is connected to the bore and pierced by a plurality of generally parallel feed passageways terminating in the bore. The third surface is generally parallel to the bore axis. The header block cooperates with a collector plate and an end plate to provide both feed and permeate manifolds. A plurality of modules comprising such blocks may be joined side by side with appropriate side plates and gaskets to provide either parallel or serial flow through permeator modules.
U.S. Pat. No. 4,083,780 to Call shows a fluid purification system comprising a pressure vessel containing a plurality of spiral wrap reverse osmosis membrane elements. The elements are placed in parallel within the pressure vessel to purify a given amount of fluid for a given diameter fluid purification apparatus.
U.S. Pat. No. 3,708,069 to Clark shows a reverse osmosis membrane module. The module includes an elongated tubular casing having substantial hoop length. The casing receives a plurality of elongated tubular membrane structures. Within the casing are a plurality of thin-walled tubes each surrounding and receiving an associated one of the tubular membranes.
U.S. Pat. No. 3,774,771 to Manjikian et al discloses a reverse osmosis module which contains a number of membrane elements each having a semi-permeable membrane covered outer surface. Each element is surrounded by a flow tube for controlling liquid flow over the membrane surface. The membrane elements are enclosed in a pressure resistant container with liquid under pressure filling the space between the outsides of the liquid flow control tubes and the interior surface of the pressure resistant container.
U.S. Pat. No. 3,485,374 to Manjikian et al. discloses a reverse osmosis module which contains a bundle of backing tubes having cast-on end flanges. The backing tubes are lined with semi-permeable membranes. Strong wrappings are placed around the ends of the bundle of tubes and are embedded in cast end flanges. An outer tube to collect product water surrounds the membrane tube bundle and is attached at its ends to the end flanges, and module end plates may be joined to connect modules in series.
U.S. Pat. No. 3,392,840 to Clark et al. discloses a reverse osmosis module which includes a porous body having a number of longitudinal bores lined with semi-permeable membranes. The body is provided with end flanges, end plates and interposed seals. Channels are formed in the body to connect the end of one bore with a pipe supplying solution to be treated under pressure, to connect the end of another bore with a pipe for concentrate exhaust, and to connect the ends of other bores to form a continuous passageway through the body.
U.S. Pat. No. 3,430,770 to Clark et al. discloses a reverse osmosis module comprising a number of backing tubes containing tubular membranes arranged in side-by-side relationship. Flanges, preferably of plastic, are cast around the ends of the tubes and these flanges contain flared bores communicating with the tube bores and which are overlaid with flared membrane ends. End plates containing connecting channels are fastened to the flanges with O-ring seals between the end plates and the flared membrane ends.